Power punch



May 30, 1950 C. H. BENOIT POWER PUNCH 3 Sheets-Sheet l J9 77 L n I l O O v C. H. BENOIT May 30, 1950 POWER PUNCH 3 Sheets-Sheet 2 Filed Nov. 1, 1946 h w Z MW, LZi-y C. H. BENOIT May 30, 1950 POWER PUNCH 3 Sheets-Sheet 5 Filed Nov. 1, 1946 FIIL me'ni'o r. CW M Patented May 30, 1950 UNITED STATES PATIENT; OFFICE 2,509,956 rowan rUNcn Conrad H. Benoit, Roslindale, Mass.

Application November 1, 1946, Serial No. 707,200

3 Claims. (Cl. 164-84) operated by the muscular power of the user, and

conventionally comprise various forms of the socalled kick press, with which unavoidable variations in the blow or pressure delivered by the working part of the machine occur through fatigue or inattention or lack of skill on the part of the operator. 'Ioo great or too little force applied in many delicate operations of the classes indicated is the cause of a serious amount of spoilage of the work in hand, with corresponding loss in economics in production. Thus, certain plastics are shattered during the above operations by a blow only moderately in excess of that required for performing such operations correctly; on the other hand, too light and cautious a blow results in incomplete punching of holes, or in the improper heading of rivets or incomplete setting of eyelets and snap fasteners, with consequent failure of the article in use or injury to it in the making. A common drawback in the kick presses operated by muscular power when employed for stamping numerals on dials, rules, and other articles, is that in the attempt to give the tool a definitely limited length of stroke a stop engaging the plunger or other working part is provided, and if the material being stamped varies in thickness, as it does in wooden rules, this variation results alternatively in a miss because the tool is stopped before traveling far enough to engage the work, or else in possible destruction of the work through penetration thereinto because not stopped in time.

An object of the present invention is to provide a device for performing these punching, pressing, slitting, riveting, shearing and related operations on light work, which shall be capable 'of performing the same operation repeatedly with unvarying force and length of stroke, but with this force, or the length of stroke, or both, being capable of variation to suit the needs of the job in hand, and with such variations designed to be of infinite degree, and in addition with the conprovide 'a' device for these uses which will be driven by electrical power, both to spare the operator from fatigue as well as to speed up the work, and also to achieve uniformity of force at any given setting. Still another object is to provide means for accurately locating the work with respect to the tool. An added object is to prevent accidental injury to the operator in the course of use of the device.

To these ends, the invention comprises a suitably guided tool-carrying reciprocating plunger which is electro-magnetically impelled. toward the work, by a controllable and variable degree of force, as by the armature of a solenoid to which the supply of actuating current is controlled in volume by means of a variable auto-transformer, variable resistance, or other suitable device whereby the power exerted upon the armature of the solenoid and on the plunger which is ac-' tuated by such armature is completely controlled and infinitely variable within the limits for which the device is built. To control and vary the range of the stroke of the plunger, the solenoid is mounted with infinite capacity for variation of its operatlvely fixed spaced relation toward and from the work-support. The auto-transformer or other current-controlling device is calibrated in a manner indicating the relative force of blow obtained at any setting thereof, and likewise a scale and index marking which are respectively located on the relatively fixed and movable parts of the solenoid mounting give a corresponding indication of the range of stroke obtained at any setting.

To locate the work accurately beneath the tool a work-holder is provided having circuit-closing means which prevents the flow of actuating current to the device and thus prevents the operation thereof unless the work is correctly positioned upon the work-holder in proper relation. In order to prevent accidental injury to the operator's hands by the movement of the tool, this workholder is designed to hold the work securely without need for manual assistance, and also in addition to the circuit-closing means associated with the work-holder two additional circuit-closers are provided in series in the current-supply circuit, each of which must be operated simultaneously with the other by one of the operator's hands, thus keeping them occupied at a safe d1 tance away from the working parts.

Other objects of the present invention, and the manner of their attainment are as made plain hereinafter.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which Fig. 1 is a side elevation, Fig. 2 a front elevation, Fig. 3 a plan view, Fig. 4 a circuit diagram,

and Fig. 5 a perspective view of the work-locater. On the base I of the tool is mounted a standard 3 adiustably supporting a slide 5, the latter car-. rying the solenoid 1 and having a frontwardly exmetrically accurate raising and lowering of the slide 5 in order to vary the range of the stroke of the plunger II, the adjusted position thus attained being retainedby tightening the screws I1. A scale marked on the beveled edge of slide 5 as indicated at 23 enables any given range of stroke toigbe predetermined.

The solenoid 1 is mounted on slide 5 by means of screws 25 driven into the slide through the butturned flanges of the frames 21 which hold the coil and the laminations of the core of the solenoid, so that its armature 3| stands and moves in axial alignment with the plunger II, a cover 23 being applied to each of these frames. The armature 3|, which is impelled downward into the core and within the coil when current is applied, is equipped with upward and downward extensions 33, 35, arranged in spaced and parallel-relation, and a bolt 31 is put through holes in the bottom extensions 35, this belt bearinga bushing 33 filling the space between the two extensions 35 and shorter bushings 3| outside the extensions 35 which latter take bearing against a the under sides of frame 21 to stop the upward travel of the moving parts as they recoil after each working stroke.

The. central bushing 33 transmits the power of the solenoid to plunger I I when the device is actuated, through resting in a V-shaped notch 43 formed for its reception in the top end of plunger I I. This simple connection between the two parts avoids difficulty in aligning the solenoid armature with respect to plunger II in setting up the parts. The plunger II and the solenoid armature are restored to their normal elevated waiting position of Fig. 1 after each downward stroke, by means of an expanding coil spring 45 coiled around the plunger and confined between the foot 9 of the slide and the flange of a, collar 31 fixed by a taper pin on the upper portion of plunger II.

The plunger works through a replaceable bushing 33 fixed in foot 3 of the slide. The proper tool for the particular operation being performed,

such as the punch 5| illustrated in the drawings,

is received in a socket formed axially in the lower end of plunger II, being retained therein by a set screw 53. I

The work holder and locater 55 is operative fixed in suitable manner on the base I. For each job, the work-supporting parts of the locater are specifically shaped to fit the exact portion of the particular piece of work which will be oper- .ated throughout the run for which this set-up of the machine is being effected, and so as to index the precise wanted spot on the work directly beneath the tool. In addition, the locater includes a movable actuator for a micro-switch. which actuator is by the act of inserting the workpiece in the locater displaced so that it closes the micro-switch, but only succeeds in doing so when the work-piece is properly fitted into the site shaped for its reception. Thus, for example, assuming that a hole is to be punched through a lug extending from the base of a molded plastic object to receive a mounting screw, a work locater as shown in Figs. 1, 2 and 5 is provided comprising a block 51 having a rearwardly and upwardly curved front face 53 aiding the operator in guiding the lug into the open end of a slot 3| formed in the under side of a plate 33 fastened on the top of block 51. The slot is made Just wide enough to receive the lug on the workpiece with friction enough to retain the lug in place, and a hole 35 is formed through top plate 33 and into the slot to permit the end of the punch 5| to strike the inserted lug at the proper point therein, a suitable recess being formed in block 51 in line with such hole to permit escape of the punchings. In this same slot 3| is slidably mounted an actuator bar 31, which is slotted for retention by screw 33 while retaining capacity for slight endwise movement. A light spring 1| anchored at one end beneath the head 0t screw 33 has its other end extending down through a slot 13 in top plate 33 into a hole in actuator 31 thus holding the latter normally forward in slot 3|; but when the lug of the work-piece has been thrust into the open end of slot 3| to the proper depth, the actuator is displaced endwise rearward to a suflicient extent such that its rear end engages the button (shown in Fig. 4) of a micro-switch 15 and thereby throws this switch into circuit-closing relation, thus preparing the tool for operation as soon as other conditions are fulfilled.

These conditions comprise the .manual actuation by the operator of two additional push button switches 11 and 13 respectively located at the left-hand and at the right-hand ends of base I of the machine, these switches being located in series with the work-actuated microswitch 15 so that all three must be simultaneously closed, the manual switches being located so far apart that both of the operator's hands are required for their actuation and both hands are thus occupied at points well away from danger of injury by the tool 5| in making its working stroke. The work-support thus not only prevents the operation of the machine upon an improperly ings 33 through an auto-transformer 35 whereby through movement of the sliding contactor 31 the voltage impressed on the windings of the coil 33 is varied to a practically infinite degree from zero to say volts or any desired top figure. This of course varies in substantially direct proportion the power of .the solenoid and hence the power of the blow or pressure exerted by the tool upon the work-piece. The contactor support, a standard -dioatedat9llocatedonthehousingotthe auto-transformer, permits easy attainment oi any desired relative degree 01' force of the blow orpressureexertedbythetoolinitsdescentby simply turning the knob, and the relative value of this force is thm predetermined, as well as being capable of instant change of known degree,

'thus also making it possible to reinstate any given degree of force after change to a different strength of blow, as for the periormanu of difierent functions. The use of the auto-transformer to control the wattage input to the solenoid windings is especially suitable for the purpose because the increase in the strength or the blow otthe tool is more nearly in direct proportion to the amount advance of the sliding contactor by manipulation of the knob 91:1. e., the auto-transformer gives more nearly a A slot Ill, Pig. 1, formed obliquely in the web of standard 8, forms a convenient hand-grip for v lifting and carrying 0 device. whichis essentially light and portable.

While I have illustrated and described a cermm in which the invention may be emam awarethat many modifications madethereinbyanypersonskilledin the art, without departing from the scope of the .expressedintheclaima'lliererore. donotwishtobelimltedtotheparticular formshowmortothedetailsotconstruction 1. A power press having in combination a work extending from the work support, aslide on the standard having a capacity for adjustment toward and from the work support, and a solenoid-and a tool-carrying plunger actuated by the latter both mounted on 2.A power puns- 20 away from the base.

a,soo,ese

in connection with the work support closing the circuit-maker only when the work is properly located on the work support, and two other normally open circuit-makers in the same circuit 5 each requiring the pressure of one of the operators hands in order to close the'circuit to the solenoid.

3. A'power press having in combination a base, a standard thereon, a slide adjustable on the standard toward and from the base, a solenoid movement of the armature and engaged and moved by the armature in the latterYs movement toward the base but not so moved in the opposite direction, and spring means on the slide urging the plunger toward the armature and CONRAD H. BENOIT.

lameness crran The following references are of record in the Number Name a Date '0 141,775, llison A118. 12, 1873 323,552 Farmer Aug. 4, 1885 831,789 Anderson Aug. 29, 1899 915,438 Hornor Mar. '16, 1909 1,273,890 'Lundgren July 23, 1918 1,502,217 Henry Apr. 27, 1926 1,807,170 Peterson May 26, 1931 1,884,888 Gury Oct. 25, 1932 1,940,980 Svenson Dec. 26. 1933 1,958,132 Davis May 8, 1934 0 2,117,880 Goddard May 17, 1938 2,155,578 Anderson Apr. 25, 1939 2,427,358 Kovach Sept. 16, 1947 FOREIGN PATENTS 5 Number Country Date 35,353 Norway July 17, 1922- 338,224 Great prltain Oct. 8. 1930 525,882 Germany Kay 29. 1931 4 705,398 France June 5, 1931 u o'rmsn one Publication. Allis-Chalmers 188M891 Review.

(for men, 1m, pp. as, a). captioned Iectromagnetic Vibrating Screens." 

